/*
 * Browser-compatible JavaScript MD5
 *
 * Modification of JavaScript MD5
 * https://github.com/blueimp/JavaScript-MD5
 *
 * Copyright 2011, Sebastian Tschan
 * https://blueimp.net
 *
 * Licensed under the MIT license:
 * https://opensource.org/licenses/MIT
 *
 * Based on
 * A JavaScript implementation of the RSA Data Security, Inc. MD5 Message
 * Digest Algorithm, as defined in RFC 1321.
 * Version 2.2 Copyright (C) Paul Johnston 1999 - 2009
 * Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet
 * Distributed under the BSD License
 * See http://pajhome.org.uk/crypt/md5 for more info.
 */
function md5(bytes: Uint8Array) {
  const words = uint8ToUint32(bytes);

  const md5Bytes = wordsToMd5(words, bytes.length * 8);
  return uint32ToUint8(md5Bytes);
}

/*
 * Convert an array of little-endian words to an array of bytes
 */
function uint32ToUint8(input: Uint32Array) {
  // Note: On little endian platforms we could simply return `new
  // Uint8Array(input.buffer)` here, but that that won't work on big-endian
  // systems.  (That said, there's code below that appears to already assume
  // little-endian, so maybe this is a moot point?  Either way, keeping the
  // existing code for now to be safe.)
  const bytes = new Uint8Array(input.length * 4);
  for (let i = 0; i < input.length * 4; i++) {
    bytes[i] = (input[i >> 2] >>> ((i % 4) * 8)) & 0xff;
  }
  return bytes;
}

/**
 * Calculate output length with padding and bit length
 */
function getOutputLength(inputLength8: number) {
  return (((inputLength8 + 64) >>> 9) << 4) + 14 + 1;
}

/*
 * Calculate the MD5 of an array of little-endian words, and a bit length.
 */
function wordsToMd5(x: Uint32Array, len: number) {
  /* append padding */
  const xpad = new Uint32Array(getOutputLength(len)).fill(0);
  xpad.set(x);
  xpad[len >> 5] |= 0x80 << len % 32;
  xpad[xpad.length - 1] = len;
  x = xpad;

  let a = 1732584193;
  let b = -271733879;
  let c = -1732584194;
  let d = 271733878;

  for (let i = 0; i < x.length; i += 16) {
    const olda = a;
    const oldb = b;
    const oldc = c;
    const oldd = d;

    a = md5ff(a, b, c, d, x[i], 7, -680876936);
    d = md5ff(d, a, b, c, x[i + 1], 12, -389564586);
    c = md5ff(c, d, a, b, x[i + 2], 17, 606105819);
    b = md5ff(b, c, d, a, x[i + 3], 22, -1044525330);
    a = md5ff(a, b, c, d, x[i + 4], 7, -176418897);
    d = md5ff(d, a, b, c, x[i + 5], 12, 1200080426);
    c = md5ff(c, d, a, b, x[i + 6], 17, -1473231341);
    b = md5ff(b, c, d, a, x[i + 7], 22, -45705983);
    a = md5ff(a, b, c, d, x[i + 8], 7, 1770035416);
    d = md5ff(d, a, b, c, x[i + 9], 12, -1958414417);
    c = md5ff(c, d, a, b, x[i + 10], 17, -42063);
    b = md5ff(b, c, d, a, x[i + 11], 22, -1990404162);
    a = md5ff(a, b, c, d, x[i + 12], 7, 1804603682);
    d = md5ff(d, a, b, c, x[i + 13], 12, -40341101);
    c = md5ff(c, d, a, b, x[i + 14], 17, -1502002290);
    b = md5ff(b, c, d, a, x[i + 15], 22, 1236535329);

    a = md5gg(a, b, c, d, x[i + 1], 5, -165796510);
    d = md5gg(d, a, b, c, x[i + 6], 9, -1069501632);
    c = md5gg(c, d, a, b, x[i + 11], 14, 643717713);
    b = md5gg(b, c, d, a, x[i], 20, -373897302);
    a = md5gg(a, b, c, d, x[i + 5], 5, -701558691);
    d = md5gg(d, a, b, c, x[i + 10], 9, 38016083);
    c = md5gg(c, d, a, b, x[i + 15], 14, -660478335);
    b = md5gg(b, c, d, a, x[i + 4], 20, -405537848);
    a = md5gg(a, b, c, d, x[i + 9], 5, 568446438);
    d = md5gg(d, a, b, c, x[i + 14], 9, -1019803690);
    c = md5gg(c, d, a, b, x[i + 3], 14, -187363961);
    b = md5gg(b, c, d, a, x[i + 8], 20, 1163531501);
    a = md5gg(a, b, c, d, x[i + 13], 5, -1444681467);
    d = md5gg(d, a, b, c, x[i + 2], 9, -51403784);
    c = md5gg(c, d, a, b, x[i + 7], 14, 1735328473);
    b = md5gg(b, c, d, a, x[i + 12], 20, -1926607734);

    a = md5hh(a, b, c, d, x[i + 5], 4, -378558);
    d = md5hh(d, a, b, c, x[i + 8], 11, -2022574463);
    c = md5hh(c, d, a, b, x[i + 11], 16, 1839030562);
    b = md5hh(b, c, d, a, x[i + 14], 23, -35309556);
    a = md5hh(a, b, c, d, x[i + 1], 4, -1530992060);
    d = md5hh(d, a, b, c, x[i + 4], 11, 1272893353);
    c = md5hh(c, d, a, b, x[i + 7], 16, -155497632);
    b = md5hh(b, c, d, a, x[i + 10], 23, -1094730640);
    a = md5hh(a, b, c, d, x[i + 13], 4, 681279174);
    d = md5hh(d, a, b, c, x[i], 11, -358537222);
    c = md5hh(c, d, a, b, x[i + 3], 16, -722521979);
    b = md5hh(b, c, d, a, x[i + 6], 23, 76029189);
    a = md5hh(a, b, c, d, x[i + 9], 4, -640364487);
    d = md5hh(d, a, b, c, x[i + 12], 11, -421815835);
    c = md5hh(c, d, a, b, x[i + 15], 16, 530742520);
    b = md5hh(b, c, d, a, x[i + 2], 23, -995338651);

    a = md5ii(a, b, c, d, x[i], 6, -198630844);
    d = md5ii(d, a, b, c, x[i + 7], 10, 1126891415);
    c = md5ii(c, d, a, b, x[i + 14], 15, -1416354905);
    b = md5ii(b, c, d, a, x[i + 5], 21, -57434055);
    a = md5ii(a, b, c, d, x[i + 12], 6, 1700485571);
    d = md5ii(d, a, b, c, x[i + 3], 10, -1894986606);
    c = md5ii(c, d, a, b, x[i + 10], 15, -1051523);
    b = md5ii(b, c, d, a, x[i + 1], 21, -2054922799);
    a = md5ii(a, b, c, d, x[i + 8], 6, 1873313359);
    d = md5ii(d, a, b, c, x[i + 15], 10, -30611744);
    c = md5ii(c, d, a, b, x[i + 6], 15, -1560198380);
    b = md5ii(b, c, d, a, x[i + 13], 21, 1309151649);
    a = md5ii(a, b, c, d, x[i + 4], 6, -145523070);
    d = md5ii(d, a, b, c, x[i + 11], 10, -1120210379);
    c = md5ii(c, d, a, b, x[i + 2], 15, 718787259);
    b = md5ii(b, c, d, a, x[i + 9], 21, -343485551);

    a = safeAdd(a, olda);
    b = safeAdd(b, oldb);
    c = safeAdd(c, oldc);
    d = safeAdd(d, oldd);
  }

  return Uint32Array.of(a, b, c, d);
}

/*
 * Convert Uint8Array to Uint32 array (little-endian)
 */
function uint8ToUint32(input: Uint8Array) {
  if (input.length === 0) {
    return new Uint32Array();
  }

  const output = new Uint32Array(getOutputLength(input.length * 8)).fill(0);
  for (let i = 0; i < input.length; i++) {
    output[i >> 2] |= (input[i] & 0xff) << ((i % 4) * 8);
  }
  return output;
}

/*
 * Add integers, wrapping at 2^32. This uses 16-bit operations internally
 * to work around bugs in some JS interpreters.
 */
function safeAdd(x: number, y: number) {
  const lsw = (x & 0xffff) + (y & 0xffff);
  const msw = (x >> 16) + (y >> 16) + (lsw >> 16);
  return (msw << 16) | (lsw & 0xffff);
}

/*
 * Bitwise rotate a 32-bit number to the left.
 */
function bitRotateLeft(num: number, cnt: number) {
  return (num << cnt) | (num >>> (32 - cnt));
}

/*
 * These functions implement the four basic operations the algorithm uses.
 */
function md5cmn(q: number, a: number, b: number, x: number, s: number, t: number) {
  return safeAdd(bitRotateLeft(safeAdd(safeAdd(a, q), safeAdd(x, t)), s), b);
}

function md5ff(a: number, b: number, c: number, d: number, x: number, s: number, t: number) {
  return md5cmn((b & c) | (~b & d), a, b, x, s, t);
}

function md5gg(a: number, b: number, c: number, d: number, x: number, s: number, t: number) {
  return md5cmn((b & d) | (c & ~d), a, b, x, s, t);
}

function md5hh(a: number, b: number, c: number, d: number, x: number, s: number, t: number) {
  return md5cmn(b ^ c ^ d, a, b, x, s, t);
}

function md5ii(a: number, b: number, c: number, d: number, x: number, s: number, t: number) {
  return md5cmn(c ^ (b | ~d), a, b, x, s, t);
}

export default md5;
